Assist features for contact hole mask patterns
US6627361B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 2001 |
| Grant date | Sep 30, 2003 |
| Priority date | — |
| Expiry date | Sep 30, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/095
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An assist feature is formed on a lithographic reticle or mask using a hybrid resist and an exposure dose such that only an annular area is effectively exposed having a width that is potentially less than the minimum feature size that can be resolved by the mask exposure tool to simultaneously or sequentially form both a feature of interest and an assist feature for enhancing imaging of the feature of interest when the feature is printed to a wafer. Since the assist feature can be imaged simultaneously with the feature of interest or multiple assist features imaged concurrently, possibly between closely spaced features, data volume and mask writing time are greatly reduced. The invention is particularly applicable to the scaling of contact holes for connections to active devices in extremely high density integrated circuits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.